23-9
Cisco Systems IntelligentGigabit Ethernet Switch Modules for the IBM BladeCenter, Software Configuration Guide
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Chapter23 Configuring QoS
Configuring Auto-QoS
Configuring Auto-QoSYou can use the auto-QoS feature to simplify the deployment of existing QoS features. Auto-QoS makes
assumptions about the network design, and as a result, the switch can prioritize different traffic flows
and appropriately use the egress queues instead of using the default QoS behavior (the switch offers
best-effort service to each packet regardless of the packet contents or size and sends it from a single
queue).
When you enable auto-QoS, it automatically classifies traffic based on the traffic type and ingress packet
label. The switch uses the resulting classification to choose the appr opriate egress queue.
You use auto-QoS commands to identify ports connected to Cisco IP Phones. You also use the
commands to identify ports that receive trusted traffic through an uplink. Auto-QoS then performs these
functions:
•Detects the presence or absence of IP phones
•Configures QoS classification
•Configures egress queues
These sections describe how to configure auto-QoS on your switch:
•Generated Auto-QoS Configuration, page 23-9
•Effects of Auto-QoS on the Configuration, page 23-11
•Configuration Guidelines, page 23-11
•Enabling Auto-QoS for VoIP, page 23-12
Generated Auto-QoS Configuration
When auto-QoS is enabled, it uses the ingress packet label to classify traffic and to configure the egress
queues as described in Table23- 2.
Table23-2 Traffic Types, Packet Labels, and Egress Queues
VoIP1 Data
Traffic
1. VoIP = voice over IP
VoIP Control
Traffic
Routing Protocol
Traffic
STP BPDU2
Traffic
2. BPDU = bridge protocol data unit
Real-Time
Video Traffic All Other Traffic
DSCP 46 24, 26 48 56 34 –
CoS 5 3 6 7 4
CoS-to-Queue
Map
5 3, 6, 7 4 2 0, 1
Egress Queue 1% WRR
(queue 4)
70% WRR (queue 3) 20% WRR
(queue 2)
20% WRR
(queue 2)
10% WRR
(queue 1)